The disclosed embodiments of the present invention relate to reducing a pin count of a chip, and more particularly, to a control chip for communicating with a wired connection interface by using a configurable pin selectively serving as an input pin (e.g., a pin used for receiving a power supply signal for connection detection) or an output pin (e.g., a pin used to output a control signal for controlling hot plug detection).
HDMI (high-definition multimedia interface) is a compact audio/video interface for transmitting digital data. For example, an HDMI source device (e.g., a set-top box, an optical disc player, a video game console, or a personal computer) is connected to an HDMI sink device (e.g., a video projector, a television, or a computer monitor) via an HDMI cable. In general, each of the HDMI source device and HDMI sink device is equipped with at least one HDMI connector (i.e., at least one HDMI port). FIG. 1 is a diagram illustrating an exemplary pin assignment of a conventional HDMI connector. A conventional control chip of an HDMI transmitter located at the HDMI source device is required to have dedicated pins coupled to pins of each HDMI connector, respectively. Similarly, a conventional control chip of an HDMI receiver located at the HDMI sink device is required to have dedicated pins coupled to pins of each HDMI connector, respectively. Taking an HDMI connector with the exemplary pin assignment shown in FIG. 1 for example, the conventional control chip needs 19 pins used for connecting the HDMI connector. Therefore, regarding the conventional control chip in the HDMI sink device, it would have one dedicated input pin connected to the 18th pin of the HDMI connector for receiving a +5V power signal generated from the HDMI source device, and one dedicated output pin connected to the 19th pin of the HDMI connector for outputting a control signal to the HDMI source device for controlling hot plug detection (HPD).
In a case where an HDMI device is equipped with more than one HDMI connector, the pin count of the conventional control chip is large. If the conventional control chip is also required to support more functions, the pin count of the conventional control chip has to be increased; otherwise, the conventional control chip may not have enough input/output pins available for these functions. As a result, the package size and the production cost of the control chip are increased inevitably.
Thus, there is a need for an innovative control chip design with a reduced number of dedicated pins used for connecting pins of an HDMI connector.